JPS6341345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, and more particularly to an improvement in a valve switching mechanism in a control valve mechanism that switches a hydraulic circuit to control supply and discharge of pressure oil from an oil pump to a power cylinder.

As a power steering device, the present applicants have already proposed in Japanese Patent Application No. 52-41199 a system that converts relative rotational displacement between an input shaft and an output shaft into a linear displacement via a link mechanism such as an Oldham joint. We proposed a system that applies this linear displacement to valve switching in a control valve mechanism. However, in this device, there is a restriction that the operating direction of the valve of the control valve mechanism extends in a direction perpendicular to the input/output axis and the central axis direction of the link mechanism. The installation position cannot necessarily be set at an arbitrary position, and depending on the vehicle type, there are certain restrictions on miniaturization of the vehicle body. Further, in order to change the valve sensitivity of the control valve mechanism, there is no simple means and it is necessary to modify a considerable part of the device.Furthermore, when adjusting the zero point of the valve mechanism, Since the valve mechanism had to be disassembled, it was desired to make it easier to change the sensitivity and adjust the zero point.

In view of the above points, it is an object of the present invention to increase the degree of freedom in the arrangement of a control valve mechanism, to reduce the size of the device, and to make it easier to change the valve sensitivity of this control valve mechanism. , a connecting member that transmits the relative rotational displacement between the input shaft and the output shaft as a reciprocating motion of the spool valve of the control valve mechanism via an Oldham joint or the like linked to these shafts;
The input/output shafts are supported centering on the axes of the input/output shafts, and the driven gear of the joint, which is supported at one end of the connecting member, revolves around the input/output shafts. It is characterized in that it is taken out for rotational displacement and rocking motion of this connecting member.

Another object of the present invention is to facilitate zero point adjustment of a control valve mechanism, and in addition to the above-mentioned configuration, rotation is transmitted from an input shaft and an output shaft to adjust the relative position between these two shafts. Among the first and second gears that take out rotational displacement, a gear support member that pivotally supports a fixed gear that is not pivotally supported by the connecting member is attached to the housing so as to be rotatably adjustable.

The present invention will be described below with reference to the illustrated embodiments.
In FIG. 1, reference numeral 1 denotes an input shaft rotatably supported in a housing 2 via a bearing 3, and is linked to a steering wheel (not shown). Reference numeral 4 denotes an output shaft rotatably supported by the housing 2 via bearings 5 and 6, which is connected to the input shaft 1 so as to be relatively rotatable, as will be described later, and is connected to a steering wheel (not shown). There is. On the other hand, the housing 2 is connected to the input shaft 1
A first housing 2a that supports the output shaft 4, a second housing 2b that supports the output shaft 4, and a disk-shaped housing that fits into the opening of the second housing 2b to partition the first and second housings 2a and 2b. It consists of a plate 2c. A cylindrical piston 7 that slides along the shaft 4 inside the second housing 2b is screwed onto the output shaft 4, and a sector gear 8a of a sector shaft 8 provided orthogonally to the output shaft 4 is screwed onto the output shaft 4. The lock teeth 7 of this cylindrical piston 7
It meshes with a. Therefore, the reciprocating movement of the piston 7 accompanying the rotation of the output shaft 4 causes the sector shaft 8 to rotate, thereby making it possible to turn a steering wheel (not shown) connected thereto. Further, this piston 7 defines the inside of the second housing 2a into hydraulic chambers A and B, and as described later, the control valve mechanism 18 is controlled by a conversion mechanism 30 that detects and converts the relative rotational displacement of the input and output shafts. This operation controls the supply and discharge of pressure oil to the hydraulic chambers A and B, thereby assisting the reciprocating movement of the piston 7 and assisting the turning operation of the steering wheel.

The input shaft 1 and the output shaft 4 are disposed on the same axis, and a protrusion formed at the tip of the input shaft 1 is connected to a bush 9 or a needle bearing that receives forces in the thrust direction and the radial direction. By fitting the input shaft 1 into a hole formed at the end of the output shaft 4, the input shaft 1 and the output shaft 4 can rotate relative to each other. As shown in FIG. 2, a plurality of grooves 11 are formed at predetermined intervals on the outer circumference of the tip 1a on the input shaft 1 side, and a plurality of grooves 11 are formed on the tip 1a on the output shaft 4 side.
a has a plurality of protrusions 12 formed at predetermined intervals on its end surface, and each groove 11 and each protrusion 1
2 are engaged with each other with a required spacing in the circumferential direction, thereby allowing the input shaft 1 and the output shaft 4 to rotate relative to each other by an amount allowed by the gap. In addition, the tip 1 of the input shaft 1
As shown in FIG. 1, the same gears 13 and 14 are respectively fixed to
Pins 15 and 16 are press-fitted and fixed at predetermined positions of each of the gears 13 and 14 so as to face each other. Both pins 15 and 1 are connected at both ends of an annular spring 17 disposed on the outer periphery of the meshing portion of the input shaft 1 and output shaft 4.
6 (see Figure 2), the spring 17 normally positions both pins 15 and 16 on the same axis, and as a result, the protrusion 12 on the output shaft 4 side normally aligns with the input shaft 1 side. The groove 11 is located at the center of the groove 11. Therefore, the input shaft 1 can be rotated relative to the output shaft 4 by the gap between the protrusion 12 and the groove 11 against the spring 17, and the external force applied to both shafts 1 and 4 is When removed, both shafts 1 and 4 are returned to their original state with zero relative rotation angle by the spring 17.

As shown in FIG. 2, the annular spring 17 is set to have a thicker wall thickness toward the center so that the stress is uniform throughout.

Next, in FIG. 3, reference numeral 18 denotes a control valve mechanism having a conventionally known configuration, and a valve hole 2d is located below the input shaft 1 in the housing 2a in a direction orthogonal thereto.
into which the spool valve 20 can be slid freely.
In the neutral position shown, pressure oil supplied from an oil pump (not shown) and introduced into the oil fill port 21 is connected to the ports 22, 23 and the spool valve 2.
By displacing the spool valve 20 in the left-right direction, the introduced pressure oil is circulated from the outlet 26 to the tank through the communication hole 20b and the central passage 20c. and said second via a pipe line (not shown).
It has a function of supplying the housing 2b, that is, the hydraulic chamber A or B of the power cylinder. Further, 19 is a connecting member for interlocking the conversion mechanism 30 described later and the spool valve 20,
The lower lever 19 of this connecting member 19 is fitted into the input shaft 1 and is rotatable around the input shaft 1.
The tip of a is engaged with a recessed fitting part 20a provided at the center of the spool valve 20. Therefore, if the connecting member 19 is rotated via the conversion mechanism 30, the spool valve 20 is displaced, thereby causing the second
The supply of pressure oil into the hydraulic chambers A and B of the housing 2b is controlled to energize the piston 7, thereby assisting in turning the steered wheels.

By the way, a spool valve 20 of the control valve mechanism 18 is connected between the control valve mechanism 18 and the input/output shafts 1 and 4 by detecting the relative rotational displacement between the two shafts 1 and 4.
A conversion mechanism 30 is provided for transmitting the power to the engine and performing the same function as a conventionally known power steering device.
In this embodiment, a conventionally well-known Oldham joint is used as the conversion mechanism 30. That is, in FIG. 1, 31 and 32 are gears of the same shape that mesh with the gears 13 and 14, respectively, and 33
34 is a protrusion with a rectangular cross section protruding from the end face of one gear 31, and 34 is the protrusion 33 on the end face of the other gear 32.
A protrusion 35 with a rectangular cross section protruding perpendicularly to the protrusion 35 is a disc interposed between the opposing protrusions 33 and 34,
An Oldham joint is constructed by slidably engaging the projections 33 and 34 with grooves cut perpendicularly to each other on both end faces of the disc 35. By rotatably supporting the rotating shaft 36 of one gear 32 constituting this Oldham joint on the plate 2c of the housing 2, and connecting the connecting member 19 to the rotating shaft 37 of the other gear 31, It constitutes the conversion mechanism 30 described above.

Reference numeral 40 designates an eccentric pin whose main body part 40a is inserted into a long hole 41 bored in the plate 2c, and an adjustment pin 40b provided offset from the axis of the main body part 40a is attached to the first housing 2a. It is embedded. Therefore, the eccentric pin 40 is rotatable around the axis of the adjustment pin 40b, and due to this rotation, the main body portion 40a presses the inner wall of the elongated hole 41 to move the plate 2c relative to the first housing 2a. It is now possible to rotate and move. That is, the plate 2 is connected via the eccentric pin 40.
By rotating c with respect to the first housing 2a, the conversion mechanism 30 can be rotated with respect to the first housing 2a, and therefore the spool valve 20 can be displaced.

With the above configuration, when the vehicle is traveling straight, that is, when the input shaft 1 and the output shaft 4 are stationary and the relative rotational displacement between them is zero,
The gears 31 and 32 of the conversion mechanism 30 that mesh with the gears 13 and 14 provided on each shaft 1 and 4 are also stationary, and in this state, the rotation shafts 36 and 37 of both gears 31 and 32 are
are located on the same axis and are connected to the rotating shaft 37 via a connecting member 19.
is held in a neutral position. Therefore, the pressure oil from the oil pump is not introduced into the second housing 2b, and the vehicle can continue to travel straight.

When a steering wheel (not shown) is operated from this state to rotate the input shaft 1, the output shaft 4 is linked to the steering wheel via the piston 7 and the sector shaft 8, and receives road resistance from the steering wheel. So,
The input shaft 1 is rotated relative to the output shaft 4 against the force of the spring 17. Then, the gear 31 that is meshed with the gear 13 fixed to the input shaft 1 tries to rotate as the input shaft 1 rotates, but the other gear that rotates integrally with this gear 31 via the Oldham joint Since the gear 32 is still meshing with the gear 14 of the output shaft 4 which is in a stationary state, the gear 31 cannot rotate with the rotation of the input shaft 1.
As a result, the gear 31 is supported and guided by the connecting member 19 and is displaced in its swinging direction.

When the gear 31 is displaced from its normal rest position, the spool valve 20, which is interlocked with the gear 31 via the connecting member 19, is also displaced from its neutral position, switching the hydraulic circuit as is well known in the art. 2. Pressure oil is supplied to the hydraulic chamber A or B of the housing 2b to assist in turning the steering wheel. When the steering wheel starts turning, the output shaft 4, which is interlocked with the steering wheel through the piston 7 and the sector shaft 8, starts rotating in the rotation direction of the input shaft 1.

When the input shaft 1 and the output shaft 4 begin to rotate at the same speed, the gear 31, which constitutes the Oldham joint,
32 also begins to rotate in the same direction at the same speed, but since the output shaft 4 is constantly receiving steering resistance from the road surface while the vehicle is turning, the input shaft 4 remains rotationally displaced relative to the input shaft 1. Therefore, the gear 31 and the valve spool 20 interlocked therewith also maintain a displaced state and continue to supply pressure oil to the second housing 2b. During this time, the driver senses the acting force of the spring 17, which attempts to return the amount of relative rotational displacement between the input and output shafts 1 and 4 to zero, as an operational reaction force. In addition, this spring 17 is connected to the input shaft 1 when the steering wheel is returned to the neutral position.
In order to return the relative rotational displacement between the output shaft 4 and the output shaft 4 to zero,
The gear 31 and the valve spool 20 are also reliably returned to their original neutral positions.

As described above, the power steering device according to this embodiment is
Since the connecting member 19 is rotatably fitted to the input shaft 1 and the spool valve 20 is displaced by swinging of the lever 19a around the shaft 1, the control valve mechanism 18 can be moved anywhere around the input shaft 1. Furthermore, since the spool valve 20 can be provided closer to the input shaft 1 than in conventional devices, it can contribute to miniaturization.
Also, to change the valve sensitivity, use the lever 19 above.
It is only necessary to change the engagement position between the lever 19a and the spool valve 20, and therefore the length of this lever 19a, that is, the connecting member 19. Therefore, there is no need to significantly modify the control valve mechanism as in the past. It is possible to change the valve sensitivity with an extremely simple operation. Furthermore, in order to adjust the zero point of the control valve mechanism 18 when assembling this device, use the eccentric pin 40.
It is only necessary to rotate the plate 2c with respect to the first housing 2a via the holder, and the operation is extremely simple. It goes without saying that the above zero point adjustment can also be performed by integrally fixing the plate 2c to the second housing 2b and rotating the first housing 2a relative to them.

In addition, as a mounting structure for the eccentric pin 40 to the housing 2, as shown in FIGS. and protrude outward from the first housing 2a,
Additionally, the adjustment pin 40b may be inserted into the elongated hole 42. According to this structure, the zero point adjustment of the control valve mechanism can be performed from the outside even after the device is assembled.

In addition, as shown in FIGS. 6a and 6b, the plate 2
A groove 4 in the thickness direction of this plate 2c is formed on the peripheral edge of the plate 2c.
3 is carved, and the main body portion 40a of the eccentric pin 40 is
It may be made to penetrate through the housing 2b and protrude outward from the second housing 2b, and the adjustment pin 40b may be engaged with the groove 43.

As described above, according to the present invention, the degree of freedom in the arrangement of the control valve mechanism is increased, the size of the apparatus is reduced, and the valve sensitivity of the control valve mechanism can be easily changed.

Further, according to the present invention, the zero point adjustment of the control valve mechanism can be performed extremely easily during or after assembly of the device.

It is clear that the power steering device according to the present invention can be applied not only to an integral type but also to a rack and pinion type.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
Figure 3 shows the - line and - line in Figure 1, respectively.
4a is a sectional view of the main part showing the mounting structure of the eccentric pin, and FIG. 4b is a sectional view taken along the line B-
A sectional view taken along line B, FIG. 4c is a side view of the eccentric pin, FIGS. 5 and 6 each show a mounting structure of the eccentric pin that is different from that in FIG. 4, and FIG. 5b is a side view of the eccentric pin, and FIG.
FIG. 6b is a sectional view taken along line BB in FIG. 6a. 1: Input shaft, 2: Housing, 2b: Power cylinder (second housing), 2c: Gear support member (plate), 4: Output shaft, 18: Control valve mechanism, 1
9: connecting member, 20: spool valve, 31: first gear, 32: second gear.

Claims (1)

[Claims] 1. An input shaft, an output shaft disposed on the same axis as the input shaft and rotatable relative to the input shaft, and a hydraulic circuit that switches the hydraulic circuit to supply pressure oil from the oil pump. a control valve mechanism that controls supply and discharge to and from the power cylinder; a first gear to which rotation is transmitted from the input shaft; a second gear to which rotation is transmitted from the output shaft; and these first and second gears. A link mechanism such as an Oldham joint that connects the two gears and transmits rotation between the two different parallel axes of the two gears, and a link mechanism such as an Oldham joint that is coaxially supported with the input/output shaft and that connects the first or second gear at one end. A connecting member is provided that pivotally supports the driven side gear and is operatively connected to the spool valve of the control valve mechanism at the other end, and the relative rotational displacement between the input and output shafts is controlled by the driven side gear around these axes. A power steering device characterized in that the power steering device is used for swinging motion of the connecting member based on the revolution displacement of a gear. 2. An input shaft, an output shaft that is arranged on the same axis as this input shaft and can rotate relative to this input shaft, and a hydraulic circuit that controls the supply and discharge of pressure oil from the oil pump to and from the power cylinder. a control valve mechanism that connects these first and second gears; a first gear that receives rotation from the input shaft; a second gear that receives rotation from the output shaft; A link mechanism such as an Oldham joint that transmits rotation between two parallel axes with different gears, and a link mechanism supported coaxially with the input/output shaft, and one end of which connects the driven gear of the first or second gear. The input/output shaft is rotatably supported by a support member that pivotally supports the fixed side gear of the two gears, and includes a connecting member that pivotally supports the spool valve of the control valve mechanism at the other end. A power steering device characterized in that it is attached to a housing so that rotation can be adjusted around these axes.